浮雕图像 · Relief Image · ▶ 在线运行案例

浮雕图像

你将学到什么

  • ShaderMaterial 自定义着色器实现核心视觉效果
  • OrbitControls 相机轨道交互
  • requestAnimationFrame 渲染循环与 resize 自适应

效果说明

本案例演示 浮雕图像 效果：基于 WebGL 实现「浮雕图像」可视化效果，附完整可运行源码；核心用到 ShaderMaterial、OrbitControls。建议先打开文首在线案例查看动态画面，再对照下方源码逐步理解。

核心概念

  • Scene / Camera / WebGLRenderer 构成最小渲染闭环；大场景可开 logarithmicDepthBuffer 缓解 Z-fighting。
  • ShaderMaterial 通过 uniforms + 自定义 GLSL 控制逐像素/逐点效果；透明粒子常配合 depthTest: false。
  • OrbitControls 提供轨道旋转/缩放；开启 enableDamping 后需在 animate 中 controls.update()。

实现步骤

  1. 搭建 Scene、PerspectiveCamera、WebGLRenderer，挂载 canvas 并处理 resize
  2. 定义 uniforms / onBeforeCompile 或 ShaderMaterial，编写 GLSL 与材质参数
  3. 创建 OrbitControls（及 Raycaster 等交互控件，若源码包含）
  4. 在 requestAnimationFrame 循环中更新状态并 render（Cesium 为 viewer.render 或自动渲染）

代码要点

import * as THREE from "three";
import { GUI } from "three/addons/libs/lil-gui.module.min.js";
import { OrbitControls } from "three/addons/controls/OrbitControls.js";
import Stats from "three/addons/libs/stats.module.js";

var container;
var scene, camera, renderer;
var controls;
var stats;

var cubeMaterial;

init();
update();
createGUI();

function init() {
    container = document.getElementById('box');

    // scene
    scene = new THREE.Scene();

    // camera
    camera = new THREE.PerspectiveCamera(45, window.innerWidth / window.innerHeight, 1, 10000);
    camera.position.set(1, 1, 1);
    camera.target = new THREE.Vector3(0, 0, 0);
    scene.add(camera);

    // renderer
    renderer = new THREE.WebGLRenderer({ antialias: true });
    renderer.setSize(window.innerWidth, window.innerHeight);
    renderer.setPixelRatio(window.devicePixelRatio);
    container.appendChild(renderer.domElement);

    controls = new OrbitControls(camera, renderer.domElement);
    controls.enableDamping = true;
    controls.minDistance = 2;
    controls.maxDistance = 10;
    stats = new Stats();
    document.body.appendChild(stats.dom);

    // light
    initLight();

    // model
    initModel();

    // event
    window.addEventListener('resize', onWindowResize, false);
}

function initLight() {
    var light = new THREE.DirectionalLight(0xffffff);
    light.position.set(0, 200, 100);
    scene.add(light);
}

// model
function initModel() {
    const cubeShader = {
        uniforms: {
            tDiffuse: { type: 't', value: new THREE.TextureLoader().load(FILE_HOST + 'threeExamples/shader/dlam.jpg') },
            fScale: { type: "float", value: 100.00 },
        },
        vertexShader: `  varying vec2 vUv;
        void main(){
          vUv = uv;
          gl_Position = projectionMatrix * modelViewMatrix * vec4(position, 1.0);
        }`,
        fragmentShader: `  varying vec2 vUv;
        uniform sampler2D tDiffuse;
        uniform float fScale;
        const highp vec3 W = vec3(0.2125, 0.7154, 0.0721);
        const vec4 bkColor = vec4(0.5, 0.5, 0.5, 1.0);
      
        void main() {
          vec2 upLeftUV = vec2(vUv.x-1.0/fScale, vUv.y-1.0/fScale);
          vec4 curColor = texture2D(tDiffuse, vUv);
          vec4 upLeftColor = texture2D(tDiffuse, upLeftUV);
          vec4 delColor = curColor - upLeftColor;
          float luminance = dot(delColor.rgb, W);
          gl_FragColor = vec4(vec3(luminance), 0.0) + bkColor;
        }`,
    }
    cubeMaterial = new THREE.ShaderMaterial({
        uniforms: cubeShader.uniforms,
        vertexShader: cubeShader.vertexShader,
        fragmentShader: cubeShader.fragmentShader,
        side: THREE.DoubleSide
    });

    var geometry = new THREE.PlaneGeometry();
    var cube = new THREE.Mesh(geometry, cubeMaterial);
    scene.add(cube);
}

function update() {
    requestAnimationFrame(update);
    renderer.render(scene, camera);

    controls.update();
    stats.update();
}

function onWindowResize() {
    var w = window.innerWidth;
    var h = window.innerHeight;
    camera.aspect = w / h;
    camera.updateProjectionMatrix();

    renderer.setSize(w, h);
}

function createGUI() {
    var gui = new GUI();
    gui.add(cubeMaterial.uniforms['fScale'], 'value', 50.0, 500.0).step(1.0).name('fScale');
}

完整源码：GitHub

小结